Fishburne, an Emmy and Tony winner, will be introduced in the ninth episode of the upcoming 10th season, the network told The Associated Press on Monday. He'll play a forensics scientist with a secret.

"I am elated and delighted to be joining the cast of `CSI,'" Fishburne said in a statement, adding that he looked forward to a "wonderful collaboration" with those involved in the series.

Fishburne plays a college lecturer and former pathologist who is focused on why people commit acts of violence.

The air date for Petersen's final episode has yet to be determined but will be early next year. Petersen has been with the series since it debuted in fall 2000 and will remain a "CSI" executive producer, the network said.

Fishburne's character has a deep connection to his work: His genetic profile has been identified in serial killers, CBS programming chief Nina Tassler said before Fishburne's casting was announced but as rumors swirled.

"This gentleman knows this about himself and is ... in this journey to discover who his true character will ultimately become," Tassler said last month — but he's keeping the crucial information to himself.

The character meets members of the "CSI" team during a murder investigation and ends up joining them.

Fishburne, 47, received an Oscar nomination for his portrayal of Ike Turner in 1993's "What's Love Got to Do With It" and a Tony in 1992 for "Two Trains Running." He was a Tony nominee this year for the one-man show, "Thurgood," about Supreme Court Justice Thurgood Marshall.

His film credits include the "Matrix" sci-fi films, in which he played Morpheus; "Apocalypse Now"; "The Color Purple"; "Mystic River"; "21"; "Akeelah and the Bee"; and "Biker Boyz." He also is a writer and director.

"CBS asked us, `Who's at the top of your dream list?'" "CSI" executive producers Carol Mendelsohn and Naren Shankar said in a joint statement. "Without hesitation, we said Laurence Fishburne. He is a powerful and intense actor, with an incredible range."

Fishburne earned an Emmy for the 1993 premiere episode of Fox's "Tribeca" and another for the movie "Miss Evers' Boys," which marked rare TV projects for the actor. Early in his career, he appeared in shows including "Miami Vice" and "Hill Street Blues."

The long-running "CSI" remains key for CBS: It finished last season as the network's top-rated series, ranking No. 9 among all shows with an average weekly audience of 17 million. Spinoffs "CSI: Miami" and "CSI: New York" ranked 16th and 28th, respectively.

Producers have been mum about upcoming plot points. But they said Petersen's character, Gil Grissom, will be reappraising his life after years of high-tech forensics investigations with the Las Vegas Police Department and after facing personal turmoil.

"CSI," which begins its new season Oct. 9, is ready to deal with Petersen's loss, said Shankar.

"What makes shows go off the rails is they forget who they are. We're a crime-mystery-forensics drama" and that won't change, Shankar said in July.